/Engine/Source/Runtime/Engine/Classes/Components/SkinnedMeshComponent.h
Cached relative transform for follower bones that are missing in the leader
struct FMissingLeaderBoneCacheEntry
int32
CommonAncestorBoneIndex
The index of the earliest common ancestor of the leader mesh.
FTransform
RelativeTransform
Relative transform of the missing bone's ref pose, based on the earliest common ancestor this will be equivalent to the component space transform of the bone had it existed in the leader.